They'll play 1960s human sexuality experts in the project based on the book by Thomas Maier.

Showtime has found a royal replacement for Paul Bettany for its Masters of Sex drama pilot.

Michael Sheen, an Emmy and BAFTA award nominee for his portrayal of former British Prime Minister Tony Blair in the telepic The Special Relationship and feature The Queen, has been tapped to play William Masters.

Meanwhile, New Girl guest star Lizzy Caplan has been tapped to co-star as Virginia Johnson, who with Masters explored the science of human sexuality and whose research touched off the sexual revolution.

The drama pilot, based on Thomas Maier's Masters of Sex: The Life and Times of William Masters and Virginia Johnson, the Couple Who Taught America How to Love, is being directed by John Madden (Shakespeare in Love) and begins production in March in New York.

The Pacific's Michelle Ashford, Judith Verno and Justified duo Sarah Timberman and Carl Beverly will serve as executive producers, while Sheen and Tammy Rosen will produce the Sony Pictures Television project.

Sheen's credits also include the Twilight franchise, arcs on 30 Rock and the U.K.'s BAFTA-nominated Fantabulosa and Dirty Filthy Love; he's repped by ICM. Caplan's credits include Mean Girls, Hot Tub Time Machine, Party Down and True Blood; she's repped by CAA.